Rob Pike posted this on Google Plus a few days ago here and I had to share it.
A few years ago I saw this page: http://www.csis.pace.edu/~bergin/patterns/ppoop.html
Local discussion focused on figuring out whether this was a joke or not. For a while, we felt it had to be even though we knew it wasn’t. Today I’m willing to admit the authors believe what is written there. They are sincere.
But… I’d call myself a hacker, at least in their terminology, yet my solution isn’t there. Just search a small table! No objects required. Trivial design, easy to extend, and cleaner than anything they present. Their “hacker solution” is clumsy and verbose. Everything else on this page seems either crazy or willfully obtuse. The lesson drawn at the end feels like misguided epistemology, not technological insight.
It has become clear that OO zealots are afraid of data. They prefer statements or constructors to initialized tables. They won’t write table-driven tests. Why is this? What mindset makes a multilevel type hierarchy with layered abstractions better than searching a three-line table? I once heard someone say he felt his job was to remove all while loops from everyone’s code, replacing them with object stuff. Wat?
But there’s good news. The era of hierarchy-driven, keyword-heavy, colored-ribbons-in-your-textook orthodoxy seems past its peak. More people are talking about composition being a better design principle than inheritance. And there are even some willing to point at the naked emperor; see http://prog21.dadgum.com/156.html for example. There are others. Or perhaps it’s just that the old guard is reasserting itself.
Object-oriented programming, whose essence is nothing more than programming using data with associated behaviors, is a powerful idea. It truly is. But it’s not always the best idea. And it is not well served by the epistemology heaped upon it.
Sometimes data is just data and functions are just functions.